Automatic stippling device



l. W. COX.

AUTOMATIC STIPPLING DEVICE.

APPLICATION FILED DEC. 2!. 1916.

1,325,715. Patented Dec. 23,1919.

2 SHEETS-SHEET 1.

J. W. COX.

AUTOMATIC STIPPLING DEVICE. APPLICATION FILED DEC. 21, 1916.

1,325,715. Patented Dec. 23,1919.

' 2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

JAMES W. COX, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO ERASTU$ I. WALCOTT, GIT CHICAGO, ILLINOIfi.

AUTOMATIC STIPPLING DEVICE.

Application filed. December 21, 1816.

To all whom it may concern Be it known that I, JAMES W. Cox, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Automatic Stippling Devices, of which the following is a specification.

Many india ink drawings of designs for architects, engineers and others require for the conventional illustration of concrete and similar materials a' stippling or dotting with ink of the entire surface representing the concrete, and as frequently the surface of the paper to be covered in this manner is of considerable extent the stippling operation as done by hand in the usual manner requires the expenditure of considerable time on the part of the skilled draftsman or engineer by whom the drawing is made. It is the object of my invention to provide an automatic apparatus which can be guided and accurately controlled by the hand of the operator to effect the vertical motion of the pen which is necessary in this work. My construction is such that it may be readily grasped and manipulated and because of the rapidity of movement of the pen far in excess of anything possible by hand the stippling is performed much more rapidly than in the hand operation and with less labor and fatigue on the part of the operator.

In the accompanying drawing I have shown and in the following specification described preferred embodiments of my invention. It will be understood, however, that the specific disclosure is for the purpose of exemplification only and that the scope of the invention is defined in the following claims in which I have endeavored to distinguish it from the prior art, so far as known to me, without, however, relinquishing or abandoning any portion or ,feature thereof.

In the drawing Figure 1 is an elevation of a preferred form of my device showing it in the hand of an operator as actually used; Fig. 2 is an elevation of the opposite side of the device from that shown in Fig. 1 with the cover plate removed to show the interior construction; Fig. 3 is a perspective view of the cover plate; Fig. 4 an elevation similar to Fig. 1 of an alternative form; Fig. 5 a side elevation of the same Specification of Letters Patent.

Patented Dec. 23, 1919.

Serial No. 138,258.

with the cover plate removed to show the lnterior construction; Fig. 6 a transverse section, and Fig. 7 an edge elevation of the device.

In the particular forms of the invention illustrated the pen is operated by electromagnetic means but in its broader aspect the invention may be involved in apparatus operated by a mechanical or other motor. In the device shown in Fig. 1 a casing 1 of sheet metal or other suitable material incloses a magnet 5, one of the ends of the coil of which is attached to a binding screw 6 of any well-known or suitable kind. The other terminal of the magnet coil is con nected to an insulated contact plate 7 mounted upon the side 8 of the casing but insulated therefrom by sheet 9. Said plate 7 carries an adjustable contact point 10 which extends through but is insulated from the casing wall 8. Preferably, and as shown, contact 10 is in the form of a screw, threaded into a boss 11 upon plate 7 and secured in adjusted position by a nut 12. The said adjustable contact is immediately over the core of the magnet 5 and the armature 13 of said magnet is interposed between the latter and the contact being supported by plate spring 14 secured at 15 to the casing. The point of attachment between the armature and spring is at the end 16 of said armature and the spring is continued beyond the point of attachment to a point immediately beneath the adjustable contact where it is provided with a refractory metal contact point 17. The bindingscrew 18 for the other conductor wire is mounted on the casbut insulated therefrom as shown, so that normally the circuit would but for such insulation be formed from binding screw 6 through wire 19, magnet 5, wire 20, bindscrew 21, plate 7, adjustable contact 10, spring contact 17 and the casing 4 to said binding screw 18. I provide, however, a spring contact-maker 22 which is attached to and in electrical connection with the binding screw 18 at 23 and extends through an opening 24 in the wall of the casing to the exterior thereof where it is formed with a finger-piece 25. The finger-piece 25 and the remainder of the spring contact are of metal and when the contact is depressed into engagement with the metal casing it closes the circuit above described through the magnet. The latter thereupon attracts its armature and the spring contact 17 following breaks the circuit with the adjustable contact 10. The magnet thereupon releases the armature so that the spring contact again completes the circuit and in this manner the armature of the magnet is rapidl vibrated.

he armature carries at its free end a: rod or extension 26 which may be soldered or otherwise secured thereto and is formed at its outer end with an eye 27 to receive a screw 28 by which a pen holder 29 having a pen 30 is angularly adjustably secured to said extension. The casing is closed by a cover plate 31 having a screw-threaded stud or sleeve 32 which when said cover plate is in place extends to the opposite side of the casing to receive a screw inserted through the aperture 33 in said casing.

Obviously when the circuit is closed in the manner heretofore described the armature of the magnet is vibrated and the pen partakes of the vibration thereof, the amplitude of movement of the pen being largely controlled by the angular adjustment described, and by the adjustment of contact 10. In operation the device is held in the hand in the manner shown in Fig. 1 and the pen having been inked is applied to the paper and the circuit closer depressed. Thereupon the pen is given a rapid vibration and by sliding the device rapidly over the surface of the paper to be stippled a series of dots is formed the distance apart of which depends upon the speed with which the device is moved. The under surface of the casing is preferably made flat and smooth to facilitate sliding it over the paper, and the pen-holder is angularly adjusted so that when the casing rests upon its base the pen may be in the proper position relative to the paper.

In the form of the invention shown in Figs. 4 to 7 the casing 33 is cylindrical and provided with a foot 34 so that when in use with the casing and foot resting upon the paper the pen 30 is in operative position. In this form of the device the magnet 35 is preferably mounted transversely of the easing with the pole pieces 36, 36 arranged as shown to attract an armature 37 carried by an arm 38 pivoted at 39 to a post 40 mounted on the casing wall. A contact spring 41 is mounted upon the back of the armature or of the lever carrying the same and when the armature is released from the magnet is held in engagement with screw contact 42 by the spring 43 attached at one end 44 to the casing and at the other to the lever 38. Screw 42 is mounted in insulating block 52, a screw 45 engages and forms electrical contact with contact 42 and a terminal plate 46 is mounted on said screw by means of a nut 47. The wire terminal 48 of the magnet winding is secured at 49 to said terminal.

plate and the other end of the magnet coil 1s secured at 50 to the binding post 51.

A second binding post 53' is secured to but insulated from the casing and carries a contact spring 53 having a contact 54 for completing the circuit when brought into contact with the wall of the casing. Casing 33, post 40 and lever 38 are of metal so that when movable contacts 54 and 41 are in engagement with their respective stationary contacts a circuit is closed from binding.

post 51 through the magnet, plate 46, screw 45, contact 42, contact 41, lever 38, post 40, the casing, contact 54, spring 53 and binding post 53. Contacts 41, 42 are normally in engagement but the circuit is normally broken at contact 54, which is closed at will by the pressure of the finger of the operator. It will be understood that when the circuit is closed at 54 the magnet attracts its armature, thereby breaking the circuit between the contacts 41, 42, whereupon the armature is released to be again attracted when the tension of the spring 43 causes the engagement of spring 41 and contact 42.

The pen 30 having been properly adjusted about its pivotal connection to the lever 38, the device is operated substantially as described in connection with the previously described modification.

By using either form of the invention in the manner described the stippling is performed with much less effort and very much more rapidly than it can pomibly be done where the pen is manipulated in the usual manner by the operator. As heretofore stated, my invention is not limited to the particular forms or embodiments thereof shown, but is defined in the claims forming a part of this specification.

I claim:

1. In a device of the class described, a

casing having a base on which it is adapted to slide on a plane surface without tilting, an electromagnet within the casing, an armature pivoted in cooperative relation with the magnet and having an arm extending outside the casing, said arm being substantially parallel to the base of the casing and elevated a substantial distance above the same, a pen mounted upon the arm and extending toward the plane of the base of the casing, electric connections for the electromagnet comprising a contact arranged to be closed and opened by the movement of the armature, and a switch extending outside the casing also in the circuit of the electromagnet for controlling the current therethrough.

2. In a device of the class described, a casing having a flat base adapted to slide upon a plane surface, an electromagnet.

mounted within the casing and upon the base thereof, an armature, a spring connectlng said armature to the casing to per- 

